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Common Symptoms of a Faulty Oil Pressure Switch

By R&D
Published on February 17th, 2025

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The Oil Pressure Switch is a vital component of an engine’s lubrication system. Typically located near the oil filter or oil pump, it is responsible for monitoring the oil pressure in the engine’s oil circulation system and controlling the oil pressure indicator on the vehicle’s instrument panel. This function is crucial for preventing engine damage, as insufficient oil pressure can lead to inadequate lubrication, resulting in increased friction and wear on engine components.

The Oil Pressure Switch consists of a pressure-sensitive diaphragm that activates electrical contact under various conditions. These conditions include when the oil pressure drops below a specified threshold, exceeds a certain upper limit, or experiences rapid fluctuations. When this occurs, the switch sends a signal to the Engine Control Module (ECM) or directly to the oil pressure warning light on the dashboard, alerting the driver to potential issues.

If the Oil Pressure Switch fails, it can lead to false warnings or, worse, a lack of warning in the event of actual low or high oil pressure. This can result in severe engine damage due to prolonged operation without adequate lubrication. Regular maintenance and timely replacement of a faulty Oil Pressure Switch are essential for ensuring the longevity and performance of the engine.

Common Symptoms of a Faulty Oil Pressure Switch

This article highlights the typical symptoms of a faulty Oil Pressure Switch, to help you identify potential issues and their root causes.

What Causes Oil Pressure Switch Failures?

Clogged Inlet Bore: Over time, contaminants such as dirt, debris, or sludge can accumulate in the inlet bore of the Oil Pressure Switch. This blockage restricts the flow of oil to the switch, potentially leading to inaccurate pressure readings or a complete failure to detect oil pressure changes.

Contact Failure on Connector: The electrical connector attached to the Oil Pressure Switch can experience contact failure due to corrosion, loose connections, or damage. This issue interrupts the electrical signals between the switch and the vehicle's monitoring system, resulting in erratic or unreliable oil pressure readings.

Internal Short-Circuit: An internal short-circuit in the Oil Pressure Switch can occur due to faulty internal wiring or components. This malfunction disrupts the switch's ability to correctly gauge oil pressure, leading to incorrect readings or the failure of the switch to activate the oil pressure warning light.

Damaged Measuring Elements: The measuring elements inside the Oil Pressure Switch, responsible for detecting and responding to oil pressure changes, can become damaged due to wear, exposure to extreme temperatures, or mechanical stress. A damaged measuring element can cause the switch to misread or fail to respond to actual oil pressure conditions.

Common Symptoms of a Faulty Oil Pressure Switch

Malfunction Indicator Light (MIL) or Check Engine Light (CEL) Illuminates

A malfunctioning Oil Pressure Switch may trigger the vehicle's On-Board Diagnostic (OBD) system to illuminate the MIL and store a corresponding Diagnostic Trouble Code (DTC) in its memory. However, the MIL can be illuminated for multiple reasons, so using a Scan Tool to diagnose the specific issue is essential.

Oil Pressure Indicator Not Operational

The oil pressure indicator on the dashboard may fail to display accurate readings or may not function altogether. This issue often stems from problems with the Oil Pressure Switch, which is responsible for sending the correct pressure data to the vehicle's monitoring system. As a result, drivers may receive misleading information or no information about the oil pressure status.

Oil Leaks

If the Oil Pressure Switch is damaged or its sealing is compromised, it can lead to oil leaks around the switch area. This leakage may be visible as oil spots or drips beneath the vehicle. Persistent oil leaks not only indicate a problem with the switch but also pose a risk of low oil levels and potential engine damage if not addressed promptly.

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Identify a Faulty Oil Pressure Switch with the Innova Scan Tool

The Innova Scan Tool quickly retrieves and identifies existing DTCs in your vehicle’s computers. With a quick OBD2 Scan, you can retrieve existing DTCs, the I/M Status of the vehicle, and any collected Freeze Frame data from these computers. Refer to the Innova Coverage Checker to determine the level of information supported on your vehicle by year, make, and model. The Innova Scan tool effectively diagnoses Oil Pressure Switch-related issues, helping you easily pinpoint and resolve problems.

Additionally, the Innova Scan Tool lets you view OBD2 Live Data PIDs and presents Original Equipment Manufacturer (OEM) Enhanced Live Data, with advanced information for complete vehicular diagnostics. You can also read the Engine Oil Pressure Input value with the Innova Scan Tool to determine if the Engine Oil Pressure Input value matches the actual Engine Oil Pressure or if it changes after many movements. The normal operating value of the Oil Pressure Switch depends on your vehicle.